Peter Popham: The footage was disturbing. But we weren't ruled by him

Elation coursed through the Libyan street yesterday like a tsunami. Assia Bashir Amry, daughter of an exiled Libyan freedom fighter, caught the mood in her tweets. "OOOMGOOOMG I just saw Gaddafi's body video," she wrote. "My heart won't stop racing... I can't believe this day has come. My whole life I've waited, prayed, wished, this is it no words."

For us, the footage of Muammar Gaddafi's body – dead or alive, who knows – being dragged off a truck by a crowd of screaming men, who then hauled it about and kicked it like a football, was deeply disturbing: the lynch mob at its most primeval. But who are we to judge? We never lived under the man's all-powerful terror.

His was like the violent death of every tyrant and the joy at the news of it was in direct proportion to the sense of injustice shared by his subjects.

Despite ruling Libya for more than 40 years, Colonel Gaddafi had failed to lay in a stock of that precious and elusive commodity – legitimacy. He lacked neither intelligence nor determination nor resourcefulness and he did everything he could think of to manufacture legitimacy. But in the end, like every tyrant, he had to fall back on naked terror. And that only works for a time.

What is legitimacy and how is it obtained? We get an inkling of what's involved in the way the monarchs of the Arab world, from Jordan to Morocco, have survived the buffeting of the Arab Spring more surely than the jumped-up lieutenants and colonels. The heart of legitimacy, according to Max Weber, the German sociologist, is that if you issue a command, it is probable that it will be obeyed. From fear, perhaps, but for other reasons, too, in particular for "affectual" reasons.

If you live in a monarchy and the king succeeds in projecting an image of paternalistic goodwill, that mystique may give you the "affect" you need. If you lived in Russia or East Germany before 1989, or North Korea even today, the relentless dinning of Marxist-Leninist propaganda, insisting that the rule of the party was leading the way to an unprecedented era of human happiness, might do the trick. Personal interest coincides with the urgings of state propaganda to persuade the mass of people that the ruler has the right to rule. Then, fear of the likely consequences of defiance clinches it.

In his eccentric, bombastic way, Colonel Gaddafi saw the need to cement his person and his role in Libya's sandy constitutional soil. He sought popularity through mass urbanisation and mass education, through the Great Man-Made Rivers Project, pumping water from under the desert, by driving up the price of oil to bring prosperity. He reinvented his country as "the Great Socialist Popular Libyan Jamahiriyah", or "State of the Masses", and with his Little Green Book, a rip-off from Mao, claimed to have invented another way, the "Third Universal Theory", following capitalism and communism.

It was pure hokum: the real source of his power was a network of spies and zero tolerance of dissent – which built up an equal and opposing weight of rage.